The invention relates to a container for single-component or multi-component molding materials, comprising a container body having a constant outer contour in a longitudinal extent of the container, a piston movable in the longitudinal direction, and a cover having an outlet opening, wherein a volume provided for a molding material is defined between the piston and the cover, the volume being variable in the direction of the longitudinal extent of the container. The invention also relates to a container system for multi-component molding materials having at least two such containers, a method for applying a mass from such a container, and a method for mixing multiple masses from such containers with such a container system using such a method.
Molding materials, especially molding materials for dental purposes, are used to produce, by molding or casting, a negative mold of an area of the body, for example a jaw or teeth, wherein this mold is then filled with a suitable material, such as gypsum (plaster of Paris), to form a positive mold of the molded area. In this way, a copy of the cast mold, called a “model,” is produced. Such models are used to produce, for example, defect prostheses or teeth replacements. They can also be used for diagnoses or treatment planning.
Because the molding mass or material must be separated from the molded object in a non-destructive way, it must be a material that solidifies relatively slowly and has an at least limited elastic or elastomeric property. Because the material must also be true to the drawing, in order to oppose a change of its surface shape with as little resistance as possible during the molding and in order to be able to transfer the assumed shape as exactly as possible to the model, suitable molding materials are usually those that are subjected to a chemical or physical change after the molding or even during the molding. Suitable molding materials are, among others, alginate, hydrocolloid, silicone, polyether, gypsum, or wax.
Here, multi-component materials are sometimes used that are stored separately from each other, for example as a base paste and as a catalyst paste, and for use are mixed together in a certain mixing ratio, for example in a ratio of five parts base paste to one part catalyst paste.
The viscous base paste and catalyst paste are stored either in cans or tubes and mixed by hand or stored in tube-bag systems or multiple-chamber cartridges and dosed by hand-driven or motor-driven devices, conveyed, and simultaneously mixed by static or rotating attachments.
For completely filling molding ladles, motor-driven devices are being used more and more, which are equipped with 360 ml to 380 ml double cartridges or tube bags. These container sizes are sufficient for ten ladle fillings, on average. Therefore, these devices are used with replaceable, rotating mixing attachments provided for one-time use. Because the mixing ratios of the base paste and catalyst paste are fixed, the devices have a common conveying feed for both components, so that the preparation time cannot be varied by the user, in which, for example, more or less catalyst paste is added relative to the base paste.
In dental practice, mixing devices have become known, for example according to European Patent EP 0 492 413 B1, which feed their reactive components in a fixed mixing ratio from double cartridges, such as according to German published patent application DE 100 38 882 A1, or double tube-bag combinations, such as according to European patent application publication EP 0 787 655 A1, and homogenize these components into mixtures by dynamic mixing attachments, such as from German Patent DE 101 64 385 C1 or German published patent application DE 101 12 904 A1, which are cross-linked to form elastomeric molding materials. The mixing ratio of the two components is here specified in currently common devices by the cross sections of the respective component container, since both components are fed with the same piston speed for discharging the container contents.
In German published patent application DE 199 51 504 A1, a mixing device is described, which can be equipped with at least two different components, in order to control the properties of the reactive mixture by a control unit. The properties to be varied are here the viscosity and the bonding time of the reactive mixture. These properties are controlled by varying the mixing ratio through separate control of the individual discharge piston speeds. In this way, an individual mixture composition can be generated from multiple different stored components. Thus, for example, in addition to the otherwise typical base and catalyst components, a viscosity component and a catalyst accelerating component can also be added.
From German published patent application DE 196 18 718 A1, the use of a decelerating component is known, which is not dosed continuously with the remaining components into the dynamic mixer, but instead is optionally injected in advance laterally into the mixer, in order to delay the curing of the mixing mass supplied at the beginning, since this mass would otherwise harden earlier than the rest of the supplied mass.
A dosing apparatus having a mixing device is disclosed in European patent application publication EP 1 836 992 A1. This apparatus discloses a holder for a double cartridge having two cartridges of different diameters, wherein a larger cartridge is provided for a base material and a smaller cartridge is provided for a catalyst material. The device has, for each of the cartridges, pistons that are pressed in sync into the cartridges in the direction of the outlet openings. The two cartridges are connected at their outlets to a mixing device having an input for each of the two cartridges. This mixing device is driven by a driveshaft that runs between the two cartridges. When the material is applied, the pistons are retracted again, so that a new double cartridge can be introduced. This dosing apparatus according to EP 1 836 992 A1 is at least twice as long as the cartridges, since in the retracted position of the pistons, the piston rods for both cartridges are arranged within the apparatus.
Force-fit connections between the drives or motors and the shafts to be driven on dynamic mixing attachments or even a screw piston drive are typically produced by hexagonal connectors. In EP 1 836 992 A1 other forms of these connections are also set forth. There, it is also described that insertion of the connection parts is made simpler.
One problem of these rigid connections is that under pressure strong stresses occur on the shafts and seals due to deformation of multiple parts of the entire system. As a result, higher friction losses occur, which significantly increase the drive energy to be applied for mixing or feeding or lead to leaks at sealing surfaces. In addition, the molding materials in the described system are preferably highly viscous, wherein their viscosity lies in the range of viscous honey to modeling clay, and thus large amounts of force must be transmitted from the drive to the piston, in order to press the material from an outlet opening. Due to the large forces occurring, the parts must have a very stable construction, which increases the material consumption, the weight, and the costs. On the other hand, the containers are susceptible to failure or can even be completely destroyed during operation.
Another disadvantage is that the replacement of the containers is time intensive due to the construction, since the drive must be connected to the shaft in a force-fit manner. Finally, it cannot be seen for the produced mixture whether the correct mixing ratio was used.